/* write0.c
 *
 * purpose: send messages to another terminal
 * method: open the other terminal for output then
 *	copy from stdin to that terminal
 * shows: a terminal is just a file supporting regular i/o
 * usage: write0 ttyname
 */
#include <stdio.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>

main(int ac, char * av[])
{
	int fd;
	char buf[BUFSIZ];
	/* check args */
	if (ac != 2)
	{
		fprintf(stderr, "usage:write0 ttyname\n");
		exit(1);
	}

	/* open devices */
	fd = open(av[1], O_WRONLY);
	if (fd == -1)
	{
		perror(av[1]); exit(1);
	}
	/* loop until EOF on input */
	while(fgets(buf, BUFSIZ, stdin) != NULL)
		if (write(fd, buf, strlen(buf)) == -1)
			break;
	close(fd);
}
